Software has conventionally been distributed in the form of programs recorded on a recording medium such as a diskette or compact disk. Customers buy the recording medium and a licence to use the software recorded on the medium, and then install the software onto their computers from the recording medium. The manufacture and distribution of the pre-recorded recording media are expensive, and this cost will be passed on to the customer. Also, the effort for customers of ordering or shopping for the software is undesirable.
The distribution cost is particularly problematic because most software products are frequently updated, both to correct bugs and to add new features, after the software has been delivered to the user. Some types of software products are updated many times each year. The cost of sending a new diskette or CD to all registered customers every time the software is upgraded or corrected is prohibitive and, although many customers want their software to be the most up-to-date, highest performance version and to be error free, not all customers want to receive every update. For example, the vendor may charge more for updates than the customer wants to spend, or new versions may require upgrading of other pre-requisite software products which the customer does not want to buy, or migrating to new versions may require migration of data which would disable the customer's system for a period of time.
Thus, software vendors tend to publicise the availability of new versions of their software and leave it for the customer to decide whether to purchase the latest upgraded version. For some software products, however, it is appropriate for the software vendor to proactively send out upgraded versions, or at least error correction and enhancement code (known as "patches") for their software products. Whatever a particular company's policy, significant costs and effort are involved in releasing these various types of software updates.
Increasingly, software distributors are using the Internet as a mechanism for publicising the availability of updates to their software, and even for distributing some software. The Internet is a network of computer networks having no single owner or controller and including large and small, public and private networks, and in which any connected computer running Internet Protocol software is, subject to security controls, capable of exchanging information with any other computer which is also connected to the Internet. This composite collection of networks which have agreed to connect to one another relies on no single transmission medium (for example, bidirectional communication can occur via satellite links, fiber-optic trunk lines, telephone lines, cable television wires and local radio links).
The World Wide Web Internet service (hereafter `the Web`) is a wide area information retrieval facility which provides access to an enormous quantity of network-accessible information and which can provide low cost communications between Internet-connected computers. It is known for software vendors, customers who have Internet access to access the vendors' Web sites to manually check lists of the latest available versions of products and then to order the products on-line. This reduces the amount of paperwork involved in ordering software (and is equally applicable to other products). Some companies have also enabled their software to be downloaded directly from a Web site on a server computer to the customer's own computer (although this download capability is often restricted to bug fixing patches, low cost programs, and demonstration or evaluation copies of programs, for security reasons and because applying patches tends not to require any change to pre-requisite software or any data migration).
Information about the World Wide Web can be found in "Spinning the Web" by Andrew Ford (International Thomson Publishing, London 1995) and "The World Wide Web Unleashed" by John December and Neil Randall (SAMS Publishing, Indianapolis 1994). Use of the WWW is growing at an explosive rate because of its combination of flexibility, portability and ease-of-use, coupled with interactive multimedia presentation capabilities. The WWW allows any computer connected to the Internet and having the appropriate software and hardware configuration to retrieve any document that has been made available anywhere on the Internet.
This increasing usage of the Internet for ordering and distribution of software has saved costs for software vendors, but for many software products the vendor cannot just rely on all customers to access his Web pages at appropriate times and so additional update mechanisms are desirable.
As well as the problem of manufacture and distribution cost associated with distributing media, there is the problem that customers typically need to make considerable proactive effort to find out whether they have the best and the latest version and release of a software product and to obtain and apply updates. Although this effort is reduced when Internet connections are available, even a requirement for proactive checking of Web sites is undesirable to many users since it involves setting up reminders to carry out checks, finding and accessing a software provider's Web site, navigating to the Web page on which latest software versions and patches are listed, and comparing version and release numbers within this list with the installed software to determine whether a relevant product update is available and to decide whether it should be ordered. There may be an annoying delay between ordering an update and it being available for use, and even if the update can be downloaded immediately the task of migrating to an upgraded version of a software product can be difficult. If these steps have to be repeated for every application, control panel, extension, utility, and system software program installed on the system then updating becomes very tedious and time consuming. Therefore, manual updating tends not to be performed thoroughly or regularly.
There is the related problem that software vendors do not know what version of their software is being used by each customer. Even if the latest version of their software has been diligently distributed to every registered customer (by sending out CDs or by server-controlled on-line distribution), there is still no guarantee that the customer has taken the trouble to correctly install the update. This takes away some of the freedom of software developers since they generally have to maintain backward compatibility with previous versions of their software or to make other concessions for users who do not upgrade.
It is known in a client-server computing environment for a system-administrator at the server end to impose new versions of software products on end users at client systems at the administrator's discretion. However, this has only been possible where the administrator has access control for updating the client's system. This takes no account of users who do not want upgrades to be imposed on them.
Yet a further related problem is that software products often require other software products to enable them to work. For example, application programs are typically written for a specific operating system. Since specific versions of one product often require specific versions of other products, upgrading a first product without upgrading others can result in the first product not working.
"Insider Updates 2.0" is a commercially available software updater utility from Insider Software Corporation which, when triggered by the user, creates an inventory of installed software on a user's Apple Macintosh computer and compares this with a database of available software update patches (but not upgraded product versions) and downloads relevant updates. "Insider Updates" shifts the responsibility for finding relevant updates from the user to the database maintainer, but the access to update patches is limited to a connection to an individual database and the tasks of scanning the Internet and on-line services to find updates and of maintaining the database of available updates require significant proactive effort. "Insider Updates" does not install the updates or modify the user's software in any way. "Insider Updates" does not address the problem of unsynchronised prerequisite software products.
A similar product which scans selected volumes of a computer system to determine the installed software and which connects to a database of software titles for the Apple Macintosh, but does not download updates, is Symmetry Software Corporation's "Version Master 1.5".
An alternative update approach is provided by "Shaman Update Server 1.1.6" from Shaman Corporation, which consists of: a CD-ROM (updated and distributed monthly) that users install on a PowerMac file server; client software for each Macintosh computer to be inventoried and updated; and means for accessing an FTP site storing a library of current updates. "Shaman Update Server" creates an inventory of networked computers and downloads and distributes latest versions of software to each computer. Network administrators centrally control this inventory and updating process. The distribution of CD-ROMs has the expense problems described earlier.